New Holland NH 6021 – Electronic Management Unit (EMU) / Transmission/Chassis Controller / XCM Controller: FWD Solenoid Stuck on

The system has detected the FWD solenoid valve is remaining in the energized or engaged position when it is commanded to be off. This is typically caused by a mechanical binding inside the solenoid valve, a melted/shorted solenoid coil, or a wiring harness short-circuiting to power.

• T4050
• T5000 series (T5030, T5060, T5070)
• T6000 series (T6010-T6070)
• T7000 series (T7030-T7060)
• T8 series
• TM115-TM175
• TS100
• Puma
• Magnum
• MXM series

1. 1

   Inspect the wiring harness leading to the FWD solenoid for naked wires, melted insulation, or rubbing that could cause a short to power or ground (wiring short cause).

2. 2

   Verify the cab FWD switch is functioning correctly and not physically stuck (switch fault cause).

3. 3

   Check the physical condition of the FWD solenoid coil for swelling or burning, which indicates a burnt-out coil sticking on the valve stem (coil failure cause).

4. 4

   Test for mechanical binding in the internal spool of the FWD solenoid valve, which may be jammed with debris or metallic shavings from the transmission/axle oil (mechanical jam cause).

1. 1

   Park and secure machine

   Park the tractor in a safe, clean location on level ground and apply the park brake.

2. 2

   Locate and clean valve area

   Locate the FWD solenoid valve. Thoroughly clean the area around the valve to prevent dirt from entering the hydraulic system.

3. 3

   Disconnect electrical connector

   Disconnect the electrical connector to the FWD solenoid.

4. 4

   Remove retaining nut

   Remove the retaining nut (often requiring a 19mm socket) that holds the electromagnetic coil to the valve stem.

5. 5

   Remove coil

   Slide the coil off. Tip: If the coil has shorted and overheated, it may be swollen. You may need to use penetrating fluid and gently pry it side-to-side to remove it.

6. 6

   Remove valve cartridge (if replacing entire assembly)

   If replacing the entire valve assembly (and not just the coil), place a catch pan underneath, as some hydraulic oil will escape. Unbolt the valve cartridge from the housing.

7. 7

   Install new parts

   Install the new FWD solenoid valve and/or coil. Torque the retaining nut to OEM specifications.

8. 8

   Reconnect wiring

   Reconnect the wiring harness (splice in a new connector if the old one was melted).

9. 9

   Clear codes and test

   Clear the fault codes from the EMU and test the 4WD engagement/disengagement.